Sludge Interface Measurement with Pulsar Measurement

Settlement tanks
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July 27, 2021 | Blog

Sludge Interface Measurement 

Why it's important and why we need it.

Sludge blanket control is a crucial part of any wastewater treatment process, and accurate monitoring of this part of the process can provide beneficial results for process efficiency and cost savings!

In the primary and secondary sedimentation stages, sewage will flow through large tanks – these are commonly called clarifiers or settlement tanks. In the primary tank, they are used to settle sludge by allowing grease and oils to rise to the surface where they are skimmed off. A rotating bridge moves around the tank at a slow speed to scrape off unwanted particles from the top of the water. The heavier sludge suspended in the wastewater will stratify to the bottom of the settlement tank. The point where this stratification occurs is referred to as the “sludge blanket.”  In secondary clarifiers/tanks, microorganisms digest the organic matter in the wastewater, creating the sludge floc which will settle at the bottom of the tank.

Sludge level measurement works by measuring the distance between the sludge blanket and the water level at the top of the tank. In the primary settlement tank, once the sludge has reached the required density, the accompanying controller will then switch on the pumps and pump the sludge into digestors, preparing it for the secondary treatment stage. In the secondary stage, there are many control factors to ensure a well performing system, but again sludge blanket level is an important one.

Once the sludge has been utilized to its full potential in the primary and secondary stages, it becomes waste sludge and undergoes further treatment, often via anaerobic digestion, thickening, dewatering, and then composting and land application as a fertilizer.Sludge Settlement Tanks

Why measure Sludge Blanket Level? 

There are many advantages and benefits from monitoring sludge blanket level, including some significant capital saving costs and a reduction in carbon footprints.

Effective sludge level measurement can help both municipal and industrial treatment plants or generate their own electricity. Many large sewage treatment works burn the gas produced in digestors to drive turbines that generate electricity. The more gas produced, the more electricity that can be generated. One of the most important determinants of gas volume is the quality and density of the sludge that is being delivered to the digestors.

In addition, operators can ensure that sludge extraction pumps are used efficiently, and excess or poorly settled sludge does not wash out into wastewater effluent paths. This can prevent costly over-spills and regulation breaches.

Further sludge handling processes, such as thickeners and dewatering equipment, perform better when fed with a higher concentration of sludge. The diluted and lower concentration sludge will require increased dosing, heating costs of digestors, and increased pumping costs.

On top of plant and operation savings, it also enables operating companies to save on labor costs of manual sampling. This means that there is a wealth of feedback instantly available, allowing for overall greater system control for plant managers and wastewater engineers worldwide!

How can I achieve effective Sludge Blanket Level Measurement? 

The Pulsar Measurement Sludge Finder 2 provides reliable and continuous sludge blanket level measurement. The Viper transducer operates ultrasonically through the wastewater by measuring the distance between the sludge blanket surface and Pulsar Measurement uses proven echo processing algorithms to identify the sludge interface level using state of the art technology. The Viper transducer with built-in external wiper blade keeps the transducer face clean and debris-free, eliminating the need for costlySludge Finder 2 Viper Transducer downtime and maintenance of a submersible sensor.

Traditionally, manual techniques of sludge blanket level measurement required engineers and operators to be exposed to wastewater and sludge for a long amount of time. Not only were these techniques labor intensive and time consuming, but they also presented health and safety issues with personnel being exposed to hazardous substances.

By automating this process with non-contacting sludge level measurement, it eliminates these issues and allows for staff to see real-time sludge blanket echo graphs on screen, without having to go near the media. The Sludge Finder 2 from Pular Measurement uses proven echo processing algorithms to identify the sludge interface level using state of the art technology. The Viper transducer with built-in external wiper blade keeps the transducer face clean and debris-free, eliminating the need for costly downtime and maintenance of a submersible sensor. 

Our sludge blanket level system can help municipal or industrial treatment plants ensure their complete treatment process is running at the highest efficiency, generate their own electricity, ensure that excess sludge is not being pumped into our local water sources, aids with compliance to health and safety and ensures compliance to environmental regulations.

For more information on our Sludge Finder 2 system, contact our knowledgeable team today.

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